Insulating material

ABSTRACT

This invention relates to self-extinguishing insulating compositions containing coolants which undergo endothermic decomposition when subjected to elevated temperature. The coolants are incorporated in various types of binder: One is combustible without leaving any solid residue. Another has the property of forming a foamed char to facilitate transpirational cooling at the heat-exposed surface. A third is incombustible. Various other substances, such as catalysts, oxidizers and plasticizers, may also be included.

United States Patent 11 1 3,714,047 Jan. 30, 1973 Marion et a1. 1 1

541 INSULATING MATERIAL 2,040,494 7/1936 Rollcghem ..117/s4 4 2,071,5592/1937 Mor an ..252 8.1 X [75] lnvcmms' hank l' :liMcspad' 2,452,054 1019411 Jonei ct a1. 252/191 x bmh 2,611,694 9/1952 Bechcr... ..252/8.l x[73] Assignee: Universal Propulsion Co., Riverside, 2,630,105 6/1954Baker X Cali/1 3,102,009 12 1904 Eichhorn ..252 s.1 x 2,928,529 3/1960Grosse et a1... ..206/.6 1 Flledi March 1970 3,536,620 10/1970 Birchall..252/7 [21] Appl. No.: 20,431

Pnmary ExaminerHar01d Ansher Related U.S. Application DataAttorney-Smyth, Roston and Pavitt 63 Continuation-inart of Ser. No.802,198, Feb. 25, 1 1969, abandoned [57] ABSTRACT This invention relatesto self-extinguishing insulating [52] U.S. Cl. ..252/62, 161/184,161/187, Compositions containing Coolants which undergo 161/1901 161/231161/403 252/3 252/44 dothermic decomposition when subjected to elevated252/71 252/81 260/25 AJ temperature. The coolants are incorporatedinvarious [51] lnt. C1. ..C09k 3/28,C04b 43/00, types of binder: one iscombustible without leaving Fleld of Search 7, 62, 3, 4; y Solidresidue. Another has the p p y f f i g 260/2'5 161/190 403 a foamed charto facilitate transpirational cooling at References Cited theheat-exposed surface. A third is incombustible.

Various other substances, such as catalysts, oxidizers and plasticizers,may also be included.

32 Claims, No Drawings INSULATING MATERIAL CROSS REFERENCE TO RELATEDAPPLICATION This application is a continuation-in-part of applicationSer. No. 802,l98 filed Feb. 25, 1969 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to heat-insulatingmaterials and more particularly to materials which decompose during theapplication of heat at elevated temperatures and which discontinue suchdecomposition immediately after the application of heat has beenterminated. Considerable work has been performed to provide materialswhich are able to serve as heat insulators when subjected to elevatedtemperatures as high as 5,000F. In spite of such work, satisfactorymaterials have not been available. One difficulty has been that thematerials continue to burn even after the application of heat has beenterminated. Another difficulty in some uses has been that the materialsliquify when subjected to heat or deposit undesirable residues upon theapplication of heat.

SUMMARY OF THE INVENTION This invention provides materials whichovercome the above disadvantages. The materials include a coolant,preferably ammonium oxalate, capable of endothermic decomposition atelevated temperatures to form gaseous products. The compositions of thisinven tion are self-extinguishing, and the heat-exposed surfaces can betouched comfortably immediately or almost immediately after theapplication of heat has been terminated.

The compositions included in this invention have further advantages. Forexample, during exposure to heat at elevated temperatures certain of thematerials included within this invention decompose and produce gaseswithout becoming liquified. The gases serve as a heat barrier tominimize further exposure to heat. The gases also allow the passage ofradio frequency signals. This is important when the compositionsincluded in this invention provide insulation in or around electronicequipment.

The compositions of this invention have other important advantages. Theycan be formulated for paint consistency or with a consistency suitablefor casting. Viscosity can also be increased so that they can beextruded, troweled, pressure-cast or molded.

In various embodiments of the invention, the coo lants are uniformlydispersed in binders having different properties. One type of binder iscombustible when subjected to heat, without leaving any solid residue.Another has the property of forming a porous char structure whichpermits passage of the gases resulting from the application of heat toprovide a transpirational cooling. A third is incombustible.

Various substances can be included in the insulating compositions ofthis invention with the binders and the coolants. For example, catalystsor curatives are included to cure the binder. In the embodiments inwhich the binder is combustible without leaving a residue, a catalyst ispreferably used which supplies oxygen to facilitate the combustion ofthe binder.

An oxidizer may also be included in the insulating I composition,particularly when the binder is combustible without leaving any residue.A plasticizer may additionally be included to render the insulatingcomposition flexible and to facilitate its combustion.

DETAILED DESCRIPTION OF THE INVENTION where R is a polyvalent organicradical containing at least one methylene group and n is an integer offrom about 3 to I00, and preferably from about 3 to 25. Preferredpolysulfides include those in which R is The polysulfides may beprepared by condensation of an alkali metal polysulfide, e.g., sodiumpolysulfide, with an organic dihalide such as dichlorodiethyl formal,ethylene dichloride, or dichloroethyl ether, as described in Industrialand Engineering Chemistry, Volume 43, pp. 324-8 (1951). Smallproportions, e.g., 0.5-2 percent, of trichloropropane or otherpolyhalides are often included with the dihalide. The polysulfides rangein property from mobile to viscous liquids to solids at roomtemperature, depending on molecular weight. Those of liquid form areordinarily preferred.

Other binders, including polyurethanes, polybutadienes and epoxideresins, can be used in place of or with the polysulfides. These bindersare advantageous because they can be compounded in liquid form and curedto a solid matrix at relatively low temperatures below approximately250F. In fact, any organic binder capable of being compounded as aliquid and cured to a solid at relatively low temperature can be used.

The epoxides, also referred to as glycidyl polyether resins, areepoxy-terminated polymers of the general formula where R is the divalentorganic radical of a dihydric alcohol or a dihydric phenol and n usuallyhas a value of from about 1 to 20.

Preferred epoxides include those in which R is The epoxides may beprepared by condensation of epichlorhydrin in alkaline medium with adihydric alcohol or a dihydric phenol such as Bisphenol A. The epoxidesrange in property from viscous liquids to low melting solids, dependingon molecular weight or degree of condensation. The degree ofcondensation is indicated by the epoxide equivalent, defined as thegrams of resin per one gram equivalent of epoxy. Epoxides are preparedwith epoxide equivalents ranging from about 140 to 4000, but those ofabout 185 to about 300 are usually preferred since these are in liquidform at room temperature.

A catalyst is generally included to cure the binder. For example, leadperoxide (PbO may be used as a catalyst when the binder is apolysulfide. This catalyst is preferably employed at a level ofapproximately seven per cent by weight of the binder, and may be used ina range of approximately six to ten per cent by weight of the binder. Inaddition to serving as a curing agent, a catalyst such as lead peroxidealso furnishes oxygen to facilitate the combustion of the binder.

Paraquinonedioxime (HON:C l-I :NOH) may be used as a catalyst instead oflead oxide when the binder is polysulfide. Paraquinonedioxime isadvantageous because it decomposes completely into gaseous products.

When polyurethane constitutes the binder, glycerine or otherhydroxyl-containing substances can serve as catalyst or curative. Thehydroxyl groups react with the isocyanate groups of the polyurethane tocure the binder. Castor oil and amines are other examples of curingagents used with polyurethane binders. Altematively, a polyol bindercontaining free hydroxyl groups can be condensed with an isocyanate suchas tolylene diisocyanate to form the polyurethane.

When epoxide resins are employed as binders, either alone or incombination with polysulfides, appropriate accelerators are thealiphatic and aromatic primary, secondary and tertiary amines, generallyemployed at levels up to about parts per 100 parts epoxide. Preferredpolyfunctional amines include 2,4,6- tri(dimethylaminomethyl)phenol,diethylenetriamine, and dimethylaminopropylamine. Other suitable aminesinclude dimethylaminomethyl phenol and benzyldimethylamine. Polyamidecuring agents may also be employed with the epoxides. Preferredpolyamides are the reaction products of polymeric fatty acids withpolyamines. The polymeric fatty acids may, for example, be dimerized andtrimerized unsaturated fatty acids derived from drying oils such assoybean oil, linseed oil, tung oil and the like. The polyamines employedfor the preparation of polyamide curatives include ethylenediamine,diethylenetriamine and the like.

A coolant, preferably ammonium oxalate (NH,) C O4-H2 is included in theinsulating composition in all the embodiments and is one of theprincipal features of the invention. The ammonium oxalate may beanhydrous or hydrated The coolant is capable of undergoing endothermicdecomposition to form gases at the elevated temperatures so that itabsorbes heat in such decomposition. For example, when ammonium oxalateis used as the coolant, it decomposes with the absorption ofapproximately 73 kilocalories per mole:

When ammonium oxalate is used as the coolant, it is preferably employedat a level of approximately three parts by weight to each part by weightof binder, particularly when the binder is polysulfide. The relativeproportion of the coolant can range from approximately one half to fourparts by weight for each part by weight of binder. Although variousammonium salts have been known as coolants, ammonium oxalate hasapparently not been known as a coolant, as may be seen from an articleentitled Sublimation Pressures and Latent Heats of Ammonium Salts byN.W. Luft in the October, 1955 issue of The Industrial Chemist.

Although ammonium oxalate is the preferred coolant, other materials maybe and have been used. For example, oxalic acid (C H O and fumaric acid(Cd-I 0) have been used as coolants and are effective. However, they aremore difficult to handle than ammonium oxalate since they constituteacids, and as such, should be used over an acid-resistant primer orbase. The acid resistant furan resins are suitable binders for use withthese coolants. The furan resins are formed by the acid-catalyzedcondensation of furfuryl alcohol. The condensation is halted at anintermediate stage by neutralization, and curing of the resultantprepolymer may be completed by addition of a strong acid catalyst afterthe coolant and any other desired ingredients have been incorporated.The unsaturated polyester resins are also appropriate binders for usewith these coolants. The polyesters are prepared by the condensation ofa glycol, such as ethylene or propylene glycol, with an unsaturateddicarboxylic acid such as fumaric acid or maleic anhydride. Physicalproperties may be varied as desired by employing a proportion ofsaturated dicarboxylic acid or aromatic dicarboxylic acid, e.g., adipicacid or phthalic anhydride, along with the unsaturated acid, forexample, by employing a 50:50 mole proportion of saturated andunsaturated acid. The polyesters are generally blended with about 10 to40 per cent by weight of low molecular weight monomer, e.g., styrene,and cured to solid products by addition of about 0.5 to 5 percent of anorganic peroxide catalyst, e.g., benzoyl peroxide, ter. butyl peroxide,or methyl ethyl ketone peroxide.

Oxamide (CONH and carbamide (urea) (NH (CONH are also theoreticallyadvantageous as coolants because they decompose endothermically.However, the gases produced are combustible to generate heat, whichneutralizes the endothermic effect of the decomposition in someapplications. Urea oxalate (2CO(NH 'C H O is also theoreticallyadvantageous, as are hydrazine compounds such as hydrazine formate (N H'2HCO H A coolant such as ammonium oxalate has been used in a bindersuch as polysulfide or a polyurethane without any additional materialother than a catalyst such as lead oxide for curing the binder. In suchmaterials, a portion of the binder may remain as a liquid film whensubjected to heat at temperatures as high as 5000F. This is notobjectionable in some applications, such as aerodynamic heat shields,where the liquid film is swept away by aerodynamic flow.

In some applications a completely gaseous end product is desired. Forexample, in the insulation of combustion chambers of gas generators, hotgas ducts or hot gas holding chambers, it is preferable that theinsulating material, particularly the binder, produce no solid char orliquid products which might interfere with the functioning of valves orcontrol devices. A completely gaseous end product also providesincreased working fluid, enabling the gas generator system to work atincreased efficiency. Similarly, in rocket motors, the gases producedfrom the insulating material facilitate the production of increasedthrust.

Where it is desired to insure that the binder will be completelyconverted to gases, a limited amount of an oxidizing compound capable ofdecomposition at elevated temperature is preferably incorporated in theinsulating composition. This oxidizer is preferably ammonium perchlorate(Nl-l ClO usually employed at a level of approximately one part byweight to each part by weight of binder. The proportion of oxidizer mayrange from zero up to approximately 1.5 parts by weight to each part byweight of binder. If the proportion of oxidizer exceeds about 1.5 partsby weight, the material no longer serves as efficiently as an insulator.

Oxidizers other than ammonium perchlorate may also be used. Ammoniumnitrate (NH NO for example, has also been found to be advantageous. Infact, almost any chlorate, perchlorate or nitrate may be used, ureanitrate and hydrazine nitrate being other examples. It is preferable touse chlorates, perchlorates, or nitrates which are free of metal cationswhere no residue is desired upon decomposition.

A plasticizer may also be included in the insulating materialconstituting this invention to render the material pliable. Glyceroltriacetate C H (OCOCH commonly designated as triacetin, is a preferredplasticizer when the binder is a polysulfide. Glycerol triacetate isadvantageous since it contains a high proportion of oxygen relative tocarbon. Furthermore, it reduces viscosity so that higher coolant levelscan be incorporated in the compositions. When subjected to heat,glycerol triacetate is combustible to form gases in substantially thesame manner as the binder. The combustion of the glycerol triacetate isfacilitated by the oxygen resulting from the decomposition of theammonium perchlorate. The plasticizer is usually employed at levels ofup to approximately thirty per cent by weight based on the binder.Glycerol triacetate levels of approximately twenty per cent by weightare preferred.

Other plasticizers may be used in place of glycerol triacetate. Forexample, dibutyl phthalate may also be used. This material isadvantageous for substantially the same reasons as glycerol triacetate,since its high oxygen content facilitates combustion, although glyceroltriacetate has the higher oxygen content. Other plasticizers, such ashigh boiling esters of polyfunctional alcohols, may be also used.

The insulating compositions constituting this invention are formed byfirst combining all ingredients except the catalyst or curative. When itis desired to form the insulating material, the curative is added to themixture, whereupon the composition cures to a solid in approximately oneto twelve hours. Curing can occur at ambient temperature when thepreferred binder, catalyst, coolant, oxidizer and plasticizer specifiedabove are employed. Alternatively, the coolant may be mixed initiallywith the catalyst and oxidizer, since they are usually all in the formof solids. This mixture may then be added to the liquid hinder orbinder-plasticizer mixture when it is desired to produce the insulatingcomposition. Whichever method is used, the mixtures produced prior tothe mixing of the binder and the catalyst may be stored for indefiniteperiods without af-' fecting the characteristics of the insulatingmaterial produced.

The insulating compositions included within this invention haveimportant advantages. When heat is applied, as from an acetylene torchat a temperature of approximately 5,000F., various decomposition andcombustion reactions ensure such that the net effect is endothermic. Ineffect, the decomposition of the coolant, binder, plasticizer andcatalyst acts as a heat sponge which more than offsets the heat releasedby the combustion. Tests have shown that the insulating material absorbsapproximately 5,000 BTU per pound. This is comparable to the materialused for the Gemini re-entry heat shield.

The compositions are self-extinguishing immediately after the heat isremoved from the surface of the insulating material, at which time thetemperature of this surface is sufficiently low that it can be touchedwithout discomfort, indicating that relatively little heat is passingthrough the insulating material. In this way, members insulated by thecompositions constituting this invention are protected againstsubstantial rise in temperature.

In view of these properties, the insulating compositions can be usedwith a pulsed source of heat to control the combustion and decompositionof the insulating material. They can also be used with a pyrotechnicheat source which does not produce any gas in itself, particularly sincethe insulating compositions produce gases when subjected to heat.

The insulating compositions constituting this invention have otherimportant advantages. For example, when used in a gas generator, theyadd to efficiency by producing gases as the insulating material isconsumed. This property is especially important in rocket motors sincethe gases generated from the insulating material impart additionalthrust.

Since the compositions of the invention are consumed in providing theinsulating action, a somewhat greater thickness may be applied initiallythan the average thickness which may be desired. This is particularlyappropriate when the insulating material is used as the external skin onrocket engines and missiles, where it provides a cool external layer asit is consumed, causing the weight of the rocket engine or missile todecrease.

The insulating compositions constituting this invention are furtheradvantageous in that the gaseous decomposition products produced areincombustible without additional oxygen. This may be seen from the factthat, when the flame from an air-acetylene torch is applied to theinsulating material, the torch must be disposed up-wind of the effluentgases or they will extinguish the torch. If the gases were combustible,the endothermic effect would be at least partially offset by thecombustion of the gases.

The insulating materials constituting this invention can beadvantageously used as a coolant around hot gases. The gases producedfrom the insulating material are relatively cool in view of theessentially endothermic nature of reaction, and they mix with the gasesto be cooled and receive heat from such gases.

The insulating compositions constituting this invention have anotherimportant advantage, viz. they allow communication at radio frequenciesthrough the gases which are produced and which envelop the insulatingmaterial. This is important when the insulating materials are used toprotect electronic systems from heat near rocket engines and withinmissiles. The gases produced from other insulating materials createimpenetrable barriers to the passage of energy at radio frequencies. Forexample, energy at radio frequencies is generally blocked by insulatorswhich carbonize or char or which decompose into metal ions. The radiofrequency transparency of the insulating materials constituting thisinvention has been proven in flight tests of Loki darts containing atransponder and coated with a preferred embodiment of the insulatingmaterial in a thickness of approximately 0.030 inches. This coating wasconsumed by aerodynamic heating during the first 30 seconds of theflight. During this period of time, communications were maintained atradio frequencies with the transponder.

The materials constituting this invention can be formulated with a paintconsistency or with suitable consistency for casting operations.Viscosity can also be increased so that the materials may be extruded,troweled, pressure-cast or molded.

A coolant such as ammonium oxalate may be used with a binder such as apolyurethane to produce an insulating material which produces anintumescent or foaming char. For example, sugar or aluminum hydroxide(Al(OH may be used as a catalyst to cure the polyurethane binder atsomewhat elevated temperature on the order of approximately 200F. Thehydroxide may be included in the insulating materials in a ratio ofapproximately five to 25 parts by weight per hundred parts by weight ofbinder, and preferably in a ratio of approximately ten parts by weightper hundred parts by weight of binder. In addition to aluminumhydroxide, the hydroxides of other metals such as iron (ferric andferrous), chromium (chromic and chromous), calcium, zirconium, platinumand magnesium may be used.

The insulating compositions described in the previous paragraph havefoaming characteristics that are produced as the binder and catalystsreact, yielding carbon dioxide as a by-product which creates aninsulation having pores. When such compositions are subjected to heat,the gases produced by decomposition and combustion move through theporous char structure to produce a transpirational cooling of theinsulating material. The movement of the gases through the charstructure facilitates the production of a gaseous interface between thechar and the heat source. The ratio of binder to coolant can be variedto provide any desired combination of char strength and density andcooling gases for a given application.

Insulating materials with foaming characteristics have relatively lowdensity, and they have good resistance to vibration and withstandphysical loads well. The amount of material required to fill a givenspace is also minimized. The aluminum hydroxide or other hydroxide maydeposit a residue of metal oxide, a possible disadvantage in certainapplications. However, for ablative coatings, such metal oxides willcontribute to'the char structure.

Insulating compositions having foaming characteristics have beenprovided with flexible as well as rigid properties. In these, thebinders have included polyurethanes and the preferred coolant has beenammonium oxalate. When insulating materials having flexible propertiesand foaming characteristics have been produced, a preferred mixture hasbeen formed from 2,4- and 2,6- tolylene diisocyanates, in approximately80/20 ratio by weight, and polyhydroxyl compounds. The polyhydroxylcompounds may be polyether or polyester polyols, or a combination ofpolyether and polyester polyols.

When the insulating materials have been provided with foamingcharacteristics and rigid properties, polyethers have been used whichare primarily propylene oxide adducts of such substances as sorbitol,sucrose, pentaeythritol, methyl glucoside and diamines. These materialshave ranged in functionality from triols to octols and in equivalentweight from to 160.

Coolants, and particularly ammonium oxalate, have also been incorporatedinto incombustible binders such as asbestos, Portland cement and plasterof Paris. With such insulating compositions, the back surface oppositethe heat-exposed surface has been maintained at a temperature below thedecomposition temperature of the ammonium oxalate until the insulatingcomposition has been completely consumed by the application of heat.

EXAMPLES 1-3 Formulations 2 and 3 are relatively stiff in compounding;formulation 1 is more readily workable and is compounded with greaterease. The cured coatings are exposed 3 inches from an acetylene torch atan oxygen pressure of 5 pounds per square inch. Under these conditions,formulation 1 exhibits an ablation rate of approximately 0.0024 inchesper second. Ablation rates of about 0.0020 and 0.0018 inches per secondare obtained with formulations 2 and 3 respectively.

The following coating compositions upon curing exhibit comparableinsulating and ablation properties.

EXAMPLE 4 I00 p. by wt. Liquid polysulfide resin (a) 25 Dibutylphthalate (plasticizer) 7.5 Lead dioxide (curing agent) 50 Ammoniumoxalate (coolant) 00.3 aluminum distearate (retarder) EXAMPLE 5 I00 p.by wt. Liquid polyurethane (b) 7.3 Amine curing agent (c) 13.2 Aminecuring agent (d) I00. Ammonium oxalate, through 60 mesh (b) ThiokolSolithane l 13 tolylene diisocyanate-urethane prepolymer hgvin anequivalent weight of 389-404 and an isocyanate content of l .6 (c)Thiokol C-l 13-300 (d)ThiokolC-l13-32ll EXAMPLES 6-9 EXAMPLES lO-llParts by Weight 10 1 l 100 Epoxide resin (e) 100 Epoxide resin (f) 10 102,4,6-tri(dimethylaminomethyl)phenol (g) 100 100 Ammonium oxalate (e)Shell Epon 828, the condensation product of epichlorhydrin and bisphenolA, having a molecular weight of 350, an epoxy value of 0.5 equivalentper 100 grams, a hydroxyl value of 0.1 equivalent per 100 ga, and anepoxide equivalent of 190-210 grams per gram mole of epoxl e.

(f) Ciba Araldite 6020 resin, having an epoxy equivalent of 208 gramsper gram mole of epoxide (g) Rohm & Haas DMP-SO (curing agent) 3OEXAMPLE 12 Parts by Wt. 60 Liquid polysulfide resin (h) 40 Epoxy resin(f) 4 2,4,6-tri(dimethylaminomethyl)phenol (g) 200 Ammonium oxalate (h)Thiokol LP-33, dithiol of molecular weight 1000, derived from 99.5 moldichloroethyl formal and 0.5 mol trichloropropane (Ind. Eng. Chem. Vol.43, p. 324, 1951) EXAMPLE 13 100 Parts by Wt. Furan resin (j) 1.0 Acidcatalyst (k) 150 Oxalic acid (3') Resin X-2, a room-setting furfurylalcohol condensation polymer available from Furane Plastics lnc., ofGlendale, California. (k) Z-lA, available from Furane Plastics lnc.

EXAMPLE 14 Parts by Wt. 100 Unsaturated polyester casting resin (l) 1.0Methyl ethyl ketone peroxide 105 Fumaric acid (I) Copolymer ofstyrcneand propylene glycol malcate-phthalate Although this invention has beendisclosed and illustrated with reference to particular applications, theprinciples involved are susceptible of numerous other applications WhlChWlll be apparent to persons skilled in the art. The invention is,therefore, to be limited only as indicated by the scope of the appendedclaims.

What is claimed is: 1. An insulating composition constituting apolymerizable liquid capable of being cured to form a solid matrix andcomprising a binder having uniformly dispersed therein a coolantsubstance capable of substantially complete endothermic decomposition atelevated temperatures above room temperatures to form gaseous products.

2. The composition of claim 1 wherein said binder is combustible to formgaseous products.

3. The composition of claim 1 additionally containing an oxidizing agentcapable of decomposition at elevated temperatures above roomtemperatures to facilitate the oxidation of said binder.

4. The composition of claim 1 additionally containing a plasticizer forsaid binder, said plasticizer being combustible to form gaseousproducts.

5. The composition of claim 1 wherein said binder is a polymerizableliquid capable of being cured to form a solid matrix.

6. The composition of claim 5 wherein the content of said coolantsubstance is in the range of above 0.5 to 4 parts by weight to 1 part byweight of said binder.

7. A self-extinguishing insulating composition, comprising an initiallyliquid polymerizable binder capable ofbeing cured to form a solidmatrix, a curing agent to polymerize said binder to the solid state, anda coolant substance capable of substantially complete endothermicdecomposition at elevated temperatures above room temperatures to formgaseous products, said binder being combustible to form gaseous productswithout leaving a residue.

8. The composition of claim 7 wherein the content of said coolantsubstance is in the range of from about 0.5 to 4 parts per part byweight of said binder.

9. The composition of claim 7 wherein said coolant substance is selectedfrom the group consisting of ammonium oxalate, oxalic acid and fumaricacid.

10. The composition of claim 9 wherein said binder is selected from thegroup consisting of polysulfides, polyurethanes and epoxide resins.

11. A self-extinguishing insulating composition comprising a combustiblebinder constituting a polymerizable liquid capable of being cured toform a solid matrix and having ammonium oxalate uniformly dispersedtherein at a level of from about 0.5 to 4 parts per part by weight ofsaid binder.

12. The composition of claim 11 additionally containing a plasticizerfor said binder, said plasticizer being combustible to form gaseousproducts without leaving a. residue.

13. The composition of claim 11 wherein said binder is selected from thegroup consisting of polysulfides, polyurethanes and epoxide resins.

14. The composition of claim 13 additionally containing ammoniumperchlorate to facilitate the oxidation of said binder.

15. An insulator, including the following substances:

a binder having properties of combusting at elevated temperatures andforming gases and constituting a polymerizable liquid capable of beingcured to form a solidmatrix;

a plasticizer having properties of combusting at elevated temperaturesabove room temperatures and forming gases;

a catalyst having properties of facilitating the curing of the binderand the combustion of the binder and the plasticizer; and

a coolant capable of substantially complete decomposition at elevatedtemperatures above room temperatures into gases in endothermic reactionwhen subjected to heat.

16. The insulator set forth in claim wherein the coolant decomposes intogases which remain at the surface of the insulator to prevent the binderand the plasticizer from combusting after the application of heat to theinsulator.

17. The insulator set forth in claim 16, further including an oxidizerhaving properties of decomposing l to provide an oxidation of the binderand the plasticizer and to form gases in providing such decomposing.

18. An insulator including the following substances:

a binder constituting a polymerizable liquid and having a hydrocarbonchain and capable of being processed as a liquid and of being cured toform a solid and having properties of combusting at elevatedtemperatures without providing any residue;

a plasticizer constituting an ester and having properties of combustingat elevated temperatures above room temperatures without providing anyresidue;

a catalyst having properties of facilitating the curing of the binderand the oxidation of the binder and the plasticizer at the elevatedtemperatures; and

a coolant capable of substantially complete decomposition at theelevated temperatures above room temperatures and of providingendothermic reactions in such decomposition.

19. An insulator as set forth in claim 18, further including an oxidizerhaving properties of decomposing at the elevated temperatures to providean oxidation of the binder and the plasticizer and to form gases inproviding such decomposing.

20. The insulator set forth in claim 18 wherein the binder constitutes amaterial formed from a group consisting of polysulfides, polyurethanes,polybutadienes, polyester resins, and epoxides;

the plasticizer constitutes a material formed from a group consisting oftriacetin, dibutyl phthalate, and high-boiling esters of polyfunctionalalcohols; and

the coolant is formed from chemical groups consisting of oxalates,oxalic acid, fumaric acid, oxamide, carbamide and hydrazine compoundsand carbamates.

21. An insulator including the following substances:

a binder constituting a polymerizable liquid and hav ing a hydrocarbonchain and capable of being processed as a liquid and of being cured toform a solid and of combusting at elevated temperatures above roomtemperatures without providing any residue;

an oxidizer having properties of substantially complete decomposition atthe elevated temperatures to provide an oxidation of the binder and toform gases in providing such decomposing; and

a coolant dispersed in the binder and capable of substantially completedecomposition at the elevated temperatures and of providing endothermicreactions in such decomposition.

22. An insulator including the following substances and havingproperties of decomposing and combusting only during the application ofheat to the insulator;

a binder having a hydrocarbon chain and capable of being processed as aliquid and of being cured to form a solid and of combusting at elevatedtemperatures without providing any residue;

an oxidizer having properties of decomposing at the elevatedtemperatures to provide an oxidation of the binder and to form gases inproviding such decomposing; and

a coolant dispersed in the binder and having properties of decomposingat the elevated temperatures and of providing endothermic reactions insuch decomposition, the binder being a polysulfide, the oxidizer beingammonium perchlorate and the coolant being ammonium oxalate.

23. The insulator set forth in claim 22 wherein the polysulfide, theammonium perchlorate and the ammonium oxalate respectively haveapproximate relative parts by weight of l one-half and 3.

24. The insulator set forth in claim 22 wherein the ammonium perchloratehas a range up to approximately 4 parts by weight to 1 part by weight ofbinder and the ammonium oxalate has a range of approximately one-half to4 parts by weight to 1 part by weight of binder.

25. An insulator, including the following substances:

a binder constituting a polymerizable liquid and having properties ofbecoming cured from a liquid to a solid and of combusting at elevatedtemperatures above room temperatures without forming a liquid; and

a coolant dispersed in the binder and capable of substantially completedecomposition into gases at the elevated temperatures in an endothermicreaction.

26. The insulator set forth in claim 25, including, a curing agent forthe binder.

27. The insulator set forth in claim 25, further including an oxidizercapable of substantially complete decomposition at the elevatedtemperatures above room temperatures to provide an oxidation of thebinder and to form gases in such decomposition.

28. The insulator set forth in claim 25 wherein the binder constitutes amaterial formed from a group consisting of polysulfides, polyurethanes,polybutadienes and epoxides;

the coolant is formed from chemical groups consisting of oxalates,oxamide, oxalic acid, fumaric acid, carbamide and hydrazine compoundsand carbamates.

29. The insulator set forth in claim 28 wherein oxidizer formed from agroup consisting of perchlorates and nitrates is included in theinsulator and is provided with properties of substantially completedecomposition at the elevated temperatures to provide an oxidation ofthe binder and to form gases in such decomposition.

30. An insulator for materials including the following substances;

a binder formed from a polymerizable liquid group consisting ofpolysulfides, polyurethanes, polybutadienes, polyester resins, andepoxides and having properties of combusting at elevated temperaturesabove room temperatures without forming any residues, the binderconstituting approximately one (1) part by weight; W

an oxidizer formed from a group consisting of chlorates, perchlorates,and nitrates and having properties of substantially completedecomposition at the elevated temperatures to provide an oxidizing ofthe binder and to form gases in providing such decomposing, the oxidizerconstituting up to approximately four (4) parts by weight;

one (1 part by weight;

a coolant formed from a group consisting of ammonium oxalates, oxamides,carbamates, oxalic acid, fumaric acid, carbamide and hydrazine comacoolant formed from a group consisting of oxalates, 5 pounds and capableof substantially complete oxamides, oxalic acid, fumaric acid, carbamidedecomposition at the elevated temperatures above and hydrazine compoundsand carbamates and room temperatures and of providing endothermiccapable of substantially complete decomposition reactions i suchdecomposition, the coolant c nat the elevated temperatures and ofproviding en- Stunting approximately three Parts y g dothermic reactionsin such decomposition, the and coolant constituting approximatelyone-half to a PlaStiCiZer r ed from a group consisting of four parts byweight; and triacetin, dibutyl phthalate, and high boiling esters aplasticizer formed from a group consisting of Of p yhy ri a1C Oh0lS andhaving a weight up to triacetin, dibutyl phthalate, and high boilingesters pp f y thirty P 0f the binder of polyhydric alcohols and having aweight up to y welghtapproximately 30 percent f the binder by weight 32.In the insulator set forth in claim 31, an oxidizer 31. in an insulatorincluding the following subformed from 3 consisting of chlorides,

stances; perchlorates and nitrates and having properties of suba binderf d f a poiymerizable liquid group stantially complete decomposition atthe elevated temconsisting of polysulfides, polyurethanes, polybu- P fabovefoom temperatures to P f l 9 tadienes, polyester resins, andepoxides having ldlzmg of the b mder and form gas es p g properties ofcombusting at elevated temperatures Such decomposmg h oxldlzer consmutmgapprox above room temperatures without forming any mately one P byresidues, the binder constituting approximately

1. An insulating composition constituting a polymerizable liquid capableof being cured to form a solid matrix and comprising a binder havinguniformly dispersed therein a coolant substance capable of substantiallycomplete endothermic decomposition at elevated temperatures above roomtemperatures to form gaseous products.
 2. The composition of claim 1wherein said binder is combustible to form gaseous products.
 3. Thecomposition of claim 1 additionally containing an oxidizing agentcapable of decomposition at elevated temperatures above roomtemperatures to facilitate the oxidation of said binder.
 4. Thecomposition of claim 1 additionally containing a plasticizer for saidbinder, said plasticizer being combustible to form gaseous products. 5.The composition of claim 1 wherein said binder is a polymerizable liquidcapable of being cured to form a solid matrix.
 6. The composition ofclaim 5 wherein the content of said coolant substance is in the range ofabove 0.5 to 4 parts by weight to 1 part by weight of said binder.
 7. Aself-extinguishing insulating composition, comprising an initiallyliquid polymerizable binder capable of being cured to form a solidmatrix, a curing agent to polymerize said binder to the solid state, anda coolant substance capable of substantially complete endothermicdecomposition at elevated temperatures above room temperatures to formgaseous products, said binder being combustible to form gaseous productswithout leaving a residue.
 8. The composition of claim 7 wherein thecontent of said coolant substance is in the range of from about 0.5 to 4parts per part by weight of said binder.
 9. The composition of claim 7wherein said coolant substance is selected from the group consisting ofammonium oxalate, oxalic acid and fumaric acid.
 10. The composition ofclaim 9 wherein said binder is selected from the group consisting ofpolysulfides, polyurethanes and epoxide resins.
 11. A self-extinguishinginsulating composition comprising a combustible binder constituting apolymerizable liquid capable of being cured to form a solid matrix andhaving ammonium oxalate uniformly dispersed therein at a level of fromabout 0.5 to 4 parts per part by weight of said binder.
 12. Thecomposition of claim 11 additionally containing a plasticizer for saidbinder, said plasticizer being combustible to form gaseous productswithout leaving a residue.
 13. The composition of claim 11 wherein saidbinder is selected from the group consisting of polysulfides,polyurethanes and epoxide resins.
 14. The composition of claim 13additionally containing ammonium perchlorate to facilitate the oxidationof said binder.
 15. An insulator, including the following substances: abinder having properties of combusting at elevated temperatures andforming gases and constituting a polymerizable liquid capable of beingcured to form a solid matrix; a plasticizer having properties ofcombusting at elevated temperatures above room temperatures and forminggases; a catalyst having properties of facilitating the curing of thebinder and the combustion of the binder and the plasticizer; and acoolant capable of substantially complete decomposition at elevatedtemperatures above room temperatures into gases in endothermic reactionwhen subjected to heat.
 16. The insulator set forth in claim 15 whereinthe coolant decomposes into gases which remain at the surface of theinsulator to prevent the binder and the plasticizer from combustingafter the application of heat to the insulator.
 17. The insulator setforth in claim 16, further including an oxidizer having properties ofdecomposing to provide an oxidation of the binder and the plasticizerand to form gases in providing such decomposing.
 18. An insulatorincluding the following substances: a binder constituting apolymerizable liquid and having a hydrocarbon chain and capable of beingprocessed as a liquid and of being cured to form a solid and havingproperties of combusting at elevated temperatures without providing anyresidue; a plasticizer constituting an ester and having properties ofcombusting at elevated temperatures above room temperatures withoutproviding any residue; a catalyst having properties of facilitating thecuring of the binder and the oxidation of the binder and the plasticizerat the elevated temperatures; and a coolant capable of substantiallycomplete decomposition at the elevated temperatures above roomtemperatures and of providing endothermic reactions in suchdecomposition.
 19. An insulator as set forth in claim 18, furtherincluding an oxidizer having properties of decomposing at the elevatedtemperatures to provide an oxidation of the binder and the plasticizerand to form gases in providing such decomposing.
 20. The insulator setforth in claim 18 wherein the binder constitutes a material formed froma group consisting of polysulfides, polyurethanes, polybutadienes,polyester resins, and epoxides; the plasticizer constitutes a materialformed from a group consisting of triacetin, dibutyl phthalate, andhigh-boiling esters of polyfunctional alcohols; and the coolant isformed from chemical groups consisting of oxalates, oxalic acid, fumaricacid, oxamide, carbamide and hydrazine compounds and carbamates.
 21. Aninsulator including the following substances: a binder constituting apolymerizable liquid and having a hydrocarbon chain and capable of beingprocessed as a liquid and of being cured to form a solid and ofcombusting at elevated temperatures aBove room temperatures withoutproviding any residue; an oxidizer having properties of substantiallycomplete decomposition at the elevated temperatures to provide anoxidation of the binder and to form gases in providing such decomposing;and a coolant dispersed in the binder and capable of substantiallycomplete decomposition at the elevated temperatures and of providingendothermic reactions in such decomposition.
 22. An insulator includingthe following substances and having properties of decomposing andcombusting only during the application of heat to the insulator; abinder having a hydrocarbon chain and capable of being processed as aliquid and of being cured to form a solid and of combusting at elevatedtemperatures without providing any residue; an oxidizer havingproperties of decomposing at the elevated temperatures to provide anoxidation of the binder and to form gases in providing such decomposing;and a coolant dispersed in the binder and having properties ofdecomposing at the elevated temperatures and of providing endothermicreactions in such decomposition, the binder being a polysulfide, theoxidizer being ammonium perchlorate and the coolant being ammoniumoxalate.
 23. The insulator set forth in claim 22 wherein thepolysulfide, the ammonium perchlorate and the ammonium oxalaterespectively have approximate relative parts by weight of 1, one-halfand
 3. 24. The insulator set forth in claim 22 wherein the ammoniumperchlorate has a range up to approximately 4 parts by weight to 1 partby weight of binder and the ammonium oxalate has a range ofapproximately one-half to 4 parts by weight to 1 part by weight ofbinder.
 25. An insulator, including the following substances: a binderconstituting a polymerizable liquid and having properties of becomingcured from a liquid to a solid and of combusting at elevatedtemperatures above room temperatures without forming a liquid; and acoolant dispersed in the binder and capable of substantially completedecomposition into gases at the elevated temperatures in an endothermicreaction.
 26. The insulator set forth in claim 25, including, a curingagent for the binder.
 27. The insulator set forth in claim 25, furtherincluding an oxidizer capable of substantially complete decomposition atthe elevated temperatures above room temperatures to provide anoxidation of the binder and to form gases in such decomposition.
 28. Theinsulator set forth in claim 25 wherein the binder constitutes amaterial formed from a group consisting of polysulfides, polyurethanes,polybutadienes and epoxides; the coolant is formed from chemical groupsconsisting of oxalates, oxamide, oxalic acid, fumaric acid, carbamideand hydrazine compounds and carbamates.
 29. The insulator set forth inclaim 28 wherein oxidizer formed from a group consisting of perchloratesand nitrates is included in the insulator and is provided withproperties of substantially complete decomposition at the elevatedtemperatures to provide an oxidation of the binder and to form gases insuch decomposition.
 30. An insulator for materials including thefollowing substances; a binder formed from a polymerizable liquid groupconsisting of polysulfides, polyurethanes, polybutadienes, polyesterresins, and epoxides and having properties of combusting at elevatedtemperatures above room temperatures without forming any residues, thebinder constituting approximately one (1) part by weight; an oxidizerformed from a group consisting of chlorates, perchlorates, and nitratesand having properties of substantially complete decomposition at theelevated temperatures to provide an oxidizing of the binder and to formgases in providing such decomposing, the oxidizer constituting up toapproximately four (4) parts by weight; a coolant formed from a groupconsisting of oxalates, oxamides, oxalic acid, fumaric acid, carbamideand hydrazine compounds and Carbamates and capable of substantiallycomplete decomposition at the elevated temperatures and of providingendothermic reactions in such decomposition, the coolant constitutingapproximately one-half to four parts by weight; and a plasticizer formedfrom a group consisting of triacetin, dibutyl phthalate, and highboiling esters of polyhydric alcohols and having a weight up toapproximately 30 percent of the binder by weight.
 31. In an insulatorincluding the following substances: a binder formed from a polymerizableliquid group consisting of polysulfides, polyurethanes, polybutadienes,polyester resins, and epoxides having properties of combusting atelevated temperatures above room temperatures without forming anyresidues, the binder constituting approximately one (1) part by weight;a coolant formed from a group consisting of ammonium oxalates, oxamides,carbamates, oxalic acid, fumaric acid, carbamide and hydrazine compoundsand capable of substantially complete decomposition at the elevatedtemperatures above room temperatures and of providing endothermicreactions in such decomposition, the coolant constituting approximatelythree (3) parts by weight; and a plasticizer formed from a groupconsisting of triacetin, dibutyl phthalate, and high boiling esters ofpolyhydric alcohols and having a weight up to approximately thirtypercent (30%) of the binder by weight.